Metal-air cells typically include a fuel electrode at which metal fuel is oxidized, an oxidant electrode at which an oxidant (i.e. oxygen from the air) is reduced, and an ionically conductive medium therebetween for providing ion conductivity between the fuel and oxidant electrodes. In some embodiments of metal-air cells, or other cells utilizing an oxidant, a wound, rolled, folded, or otherwise compacted configuration may be utilized for enhancing cell space management and arrangement. In some such cells, multiple layers are formed that include the fuel electrode, the oxidant electrode, and the ionically conductive medium. The layers may then be rolled, wound, folded, or so on. Examples of such cells are disclosed in U.S. Patent Application Publication No. 2010/0285375, and U.S. application Ser. Nos. 12/776,962, 61/177,072 and 61/267,240, the entireties of which are incorporated herein by reference.
It may be appreciated that reducing the thickness of one or more of the layers of the cell may have a compounded advantage, due to the repetitive increase in thickness as the layers are wound around themselves, or folded back onto themselves. Likewise, such compounded advantages may additionally or alternatively be realized by combining the functionality of one or more of the layers of the cell. Thus, it is apparent that the reduction in thickness or elimination of one or more of the layers of such cells may greatly increase the energy and/or power density of the cell, allowing for smaller and/or more powerful batteries.
It may be appreciated that each of the broader layers of the cell (such as the oxidant electrode and the fuel electrode, for example) may be typically comprised of multiple layers of constituent materials (i.e. constituent layers). For example, in a conventional oxidant electrode that is utilized in an electrochemical cell having a liquid or semi-liquid ionically conductive medium, the oxidant electrode may have an air permeable but ionically conductive medium impermeable (i.e. liquid impermeable) layer, a catalyzed active layer, and a conductor layer. Accordingly, the benefit of a reduction in thickness of any constituent layer, or the benefit of combining any of the constituent layers, may be compounded if the layers of the cell are subsequently wound around themselves or folded back onto themselves.